1. Technical Field
The disclosure generally relates to a touch panel, more particularly, the disclosure relates to a touch panel with parallel electrodes.
2. Description of the Related Art
Nowadays, the most popular touch panels sold in the market are generally classifiable as resistive-type and capacitive-type touch panels. The resistive-type can also be classified into 4-wire resistive-type, 5-wire resistive-type, 6-wire resistive-type, 7-wire resistive-type and 9-wire resistive-type. The capacitive-type can be classified into surface capacitive touch screen (SCT) and projective capacitive touch screen (PCT) which also designated digital-touch technology. The resistive-type and the surface capacitive touch screen (SCT) are generally designated analog-touch technology.
In recent years, the most popular analog-touch technology has generally used an input controlled by a 4-point voltage supply, as mentioned in U.S. Pat. Nos. 3,798,370A, 4,371746A, 4,661,655A, 4,731,508A, 4,797,514A, 4,822,957A, 4,933,660A, 5,804,773A, 5,815,141A, 6,396,484B1,6,630,929B1, 7,148,881B2, 7,265,686B2, 7,307,626B2 etc. For touch detection, they usually control the input source by inputting the controlled voltage in four corners.
For example, the operating principal of surface capacitive touch screen is as follows: A uniform electrical field is formed on the ITO layer. The capacitive charge effect results from the panel being touch by the fingers. The capacitance-coupled effect between the transparent electrodes and fingers causes current variation in the panel. Thus, the controlled devices can calculate the position of contact by means of measuring the current magnitude of four electrodes in four corners.
Please refer to FIG. 1, which shows a schematic diagram of a five-wire touch panel 10 of the related art. By using the electrode wires, the voltage controlled unit (un-sketched) located outside the touch panel connects the four electrodes, A, B, C and D of conductive layer 11 to the electrode plates, PA, PB, PC and PD. Moreover, the PE is connected to the touch layer (un-sketched). The conductive layer enclosed by the chains of series resistances, CAR-YU, CAR-YD, CAR-XR and CAR-XL around conductive layer 11, is the effective touch area. The four electrodes, A, B, C and D generate a uniformly distributed electrical field which is used for position detecting of resistive-type and the surface capacitive touch screens (SCT) by means of by the chains of series resistances, CAR-YU, CAR-YD, CAR-XR and CAR-XL around conductive layer 11, and the voltage of voltage controlled unit.
Please refer to FIG. 2 and FIG. 3, which show the schematic diagrams of a controlled mode of detecting voltage in the y-axis, and detecting voltage in the y-axis, of the touch panel. Now refer to FIG. 2, which is a schematic diagram of a controlled mode of detecting a voltage in the y-axis of the touch panel. As the voltage controlled unit inputs voltages to the electrode plates (where PA=+5V, PB=0V, PC=0V and PD=+5V), an electrical field is generated within chains of series resistances, CAR-YU, CAR-YD, CAR-XR and CAR-XL around conductive layer 11, as shown in FIG. 2, where the dash-line is the equipotential line and the solid-line indicates the direction of the current. The touched position in y-axis can be detected, as an object is contacting the touch panel. Now refer to FIG. 3, which is a schematic diagram of a controlled mode of detecting voltage in the x-axis of the touch panel. As the voltage controlled unit inputs voltages to the electrode plates (where PA=+5V, PB=+5V, PC=0V and PD=0V), an electrical field is generated within chains of series resistances, CAR-YU, CAR-YD, CAR-XR and CAR-XL around conductive layer 11 as shown in FIG. 3, where the dash-line is the equipotential line and the solid-line indicates the direction of the current. The touched position in x-axis can be detected, as an object is contacting the touch panel.
However, touch panel technology has matured considerably over the last two or 10 three decades, with the increasing development of technology. Therefore, the latest trend in touch panel technology is economic, for example, the reduction of frame size, low power consumption or the request of uniformity of electrical field distribution in the frame, especially in the corners. Consequently, every touch panel factory and store of continues to develop their technology further, as a result of competition.